Change your SMTP server to current ISP

Out going email always has to go via the ISP you are connected to. If you are not connected via Eclipse you will not be able to send emails via Eclipse and I would be very surprised if you have done so in the past. There are too many spammers looking for open relays for an ISP to leave their email server open.

Point your outgoing mail at your current ISPs mail server and everything will work fine. Your incoming mail server can stay at Eclipse. That won't be a problem.